/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License. You may obtain a
 * copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package jacky.lanlan.song.io;

import jacky.lanlan.song.io.stream.ByteArrayOutputStream;

import java.io.*;
import java.net.Socket;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

/**
 * General IO stream manipulation utilities.
 * <p>
 * This class provides static utility methods for input/output operations.
 * <ul>
 * <li>closeQuietly - these methods close a stream ignoring nulls and exceptions
 * <li>toXxx/read - these methods read data from a stream
 * <li>write - these methods write data to a stream
 * <li>copy - these methods copy all the data from one stream to another
 * <li>contentEquals - these methods compare the content of two streams
 * </ul>
 * <p>
 * The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are
 * provided in each case, one that uses the platform default encoding and the other which allows you
 * to specify an encoding. You are encouraged to always specify an encoding because relying on the
 * platform default can lead to unexpected results, for example when moving from development to
 * production.
 * <p>
 * All the methods in this class that read a stream are buffered internally. This means that there
 * is no cause to use a <code>BufferedInputStream</code> or <code>BufferedReader</code>. The default
 * buffer size of 4K has been shown to be efficient in tests.
 * <p>
 * Wherever possible, the methods in this class do <em>not</em> flush or close the stream. This is
 * to avoid making non-portable assumptions about the streams' origin and further use. Thus the
 * caller is still responsible for closing streams after use.
 * <p>
 * Origin of code: Excalibur.
 * 
 * @author Peter Donald
 * @author Jeff Turner
 * @author Matthew Hawthorne
 * @author Stephen Colebourne
 * @author Gareth Davis
 * @author Ian Springer
 * @author Niall Pemberton
 * @author Sandy McArthur
 * @version $Id: IOUtils.java 481854 2006-12-03 18:30:07Z scolebourne $
 */
public abstract class IOUtils {
	// NOTE: This class is focussed on InputStream, OutputStream, Reader and
	// Writer. Each method should take at least one of these as a parameter,
	// or return one of them.

	/**
	 * The Unix directory separator character.
	 */
	public static final char DIR_SEPARATOR_UNIX = '/';

	/**
	 * The Windows directory separator character.
	 */
	public static final char DIR_SEPARATOR_WINDOWS = '\\';

	/**
	 * The system directory separator character.
	 */
	public static final char DIR_SEPARATOR = File.separatorChar;

	/**
	 * The Unix line separator string.
	 */
	public static final String LINE_SEPARATOR_UNIX = "\n";

	/**
	 * The Windows line separator string.
	 */
	public static final String LINE_SEPARATOR_WINDOWS = "\r\n";

	/**
	 * The system line separator string.
	 */
	public static final String LINE_SEPARATOR;
	static {
		// avoid security issues
		StringWriter buf = new StringWriter(4);
		PrintWriter out = new PrintWriter(buf);
		out.println();
		LINE_SEPARATOR = buf.toString();
	}

	/**
	 * The default buffer size to use.
	 */
	private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

	// -----------------------------------------------------------------------
	/**
	 * Unconditionally close an <code>Reader</code>.
	 * <p>
	 * Equivalent to {@link Reader#close()}, except any exceptions will be ignored. This is typically
	 * used in finally blocks.
	 * 
	 * @param input
	 *          the Reader to close, may be null or already closed
	 */
	public static void close(Reader input) {
		closeQuietly(input);
	}

	/**
	 * Unconditionally close a <code>Writer</code>.
	 * <p>
	 * Equivalent to {@link Writer#close()}, except any exceptions will be ignored. This is typically
	 * used in finally blocks.
	 * 
	 * @param output
	 *          the Writer to close, may be null or already closed
	 */
	public static void close(Writer output) {
		closeQuietly(output);
	}

	/**
	 * Unconditionally close an <code>InputStream</code>.
	 * <p>
	 * Equivalent to {@link InputStream#close()}, except any exceptions will be ignored. This is
	 * typically used in finally blocks.
	 * 
	 * @param input
	 *          the InputStream to close, may be null or already closed
	 */
	public static void close(InputStream input) {
		closeQuietly(input);
	}

	/**
	 * Unconditionally close an <code>OutputStream</code>.
	 * <p>
	 * Equivalent to {@link OutputStream#close()}, except any exceptions will be ignored. This is
	 * typically used in finally blocks.
	 * 
	 * @param output
	 *          the OutputStream to close, may be null or already closed
	 */
	public static void close(OutputStream output) {
		closeQuietly(output);
	}

	/**
	 * Unconditionally close an <code>Closeable</code>.
	 * <p>
	 * Equivalent to {@link Closeable#close()}, except any exceptions will be ignored. This is
	 * typically used in finally blocks.
	 * 
	 * @param closeables
	 *          the Closeable list to close, may be null or already closed
	 */
	public static void closeQuietly(final Closeable... closeables) {
		for (Closeable c : closeables) {
			if (c != null) {
				try {
					c.close();
				}
				catch (IOException e) {
				}
			}
		}
	}

	public static void closeQuietly(final Socket socket) {
		try {
			socket.close();
		}
		catch (IOException e) {}
	}
	
	public static void closeQuietly(final SocketChannel channel) {
		final Socket socket = channel.socket();
		try {
			socket.close();
		}
		catch (IOException e) {}
		try {
			channel.close();
		}
		catch (IOException e) {}
	}

	// read toByteArray
	// -----------------------------------------------------------------------
	/**
	 * Get the contents of an <code>InputStream</code> as a <code>byte[]</code>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @return the requested byte array
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 */
	public static byte[] toByteArray(InputStream input) throws IOException {
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		copy(input, output);
		return output.toByteArray();
	}

	/**
	 * Get the contents of a <code>Reader</code> as a <code>byte[]</code> using the default character
	 * encoding of the platform.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @return the requested byte array
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 */
	public static byte[] toByteArray(Reader input) throws IOException {
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		copy(input, output);
		return output.toByteArray();
	}

	/**
	 * Get the contents of a <code>Reader</code> as a <code>byte[]</code> using the specified
	 * character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @return the requested byte array
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static byte[] toByteArray(Reader input, String encoding) throws IOException {
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		copy(input, output, encoding);
		return output.toByteArray();
	}

	// read char[]
	// -----------------------------------------------------------------------
	/**
	 * Get the contents of an <code>InputStream</code> as a character array using the default
	 * character encoding of the platform.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param is
	 *          the <code>InputStream</code> to read from
	 * @return the requested character array
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static char[] toCharArray(InputStream is) throws IOException {
		CharArrayWriter output = new CharArrayWriter();
		copy(is, output);
		return output.toCharArray();
	}

	/**
	 * Get the contents of an <code>InputStream</code> as a character array using the specified
	 * character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param is
	 *          the <code>InputStream</code> to read from
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @return the requested character array
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static char[] toCharArray(InputStream is, String encoding) throws IOException {
		CharArrayWriter output = new CharArrayWriter();
		copy(is, output, encoding);
		return output.toCharArray();
	}

	/**
	 * Get the contents of a <code>Reader</code> as a character array.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @return the requested character array
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static char[] toCharArray(Reader input) throws IOException {
		CharArrayWriter sw = new CharArrayWriter();
		copy(input, sw);
		return sw.toCharArray();
	}

	// read toString
	// -----------------------------------------------------------------------
	/**
	 * Get the contents of an <code>InputStream</code> as a String using the default character
	 * encoding of the platform.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @return the requested String
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 */
	public static String toString(InputStream input) throws IOException {
		StringWriter sw = new StringWriter();
		copy(input, sw);
		return sw.toString();
	}

	/**
	 * Get the contents of an <code>InputStream</code> as a String using the specified character
	 * encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @return the requested String
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 */
	public static String toString(InputStream input, String encoding) throws IOException {
		StringWriter sw = new StringWriter();
		copy(input, sw, encoding);
		return sw.toString();
	}

	/**
	 * Get the contents of a <code>Reader</code> as a String.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @return the requested String
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 */
	public static String toString(Reader input) throws IOException {
		StringWriter sw = new StringWriter();
		copy(input, sw);
		return sw.toString();
	}

	// readLines
	// -----------------------------------------------------------------------
	/**
	 * Get the contents of an <code>InputStream</code> as a list of Strings, one entry per line, using
	 * the default character encoding of the platform.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from, not null
	 * @return the list of Strings, never null
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static List<String> readLines(InputStream input) throws IOException {
		InputStreamReader reader = new InputStreamReader(input);
		return readLines(reader);
	}

	/**
	 * Get the contents of an <code>InputStream</code> as a list of Strings, one entry per line, using
	 * the specified character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from, not null
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @return the list of Strings, never null
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static List<String> readLines(InputStream input, String encoding) throws IOException {
		if (encoding == null) { return readLines(input); }
		InputStreamReader reader = new InputStreamReader(input, encoding);
		return readLines(reader);
	}

	/**
	 * Get the contents of a <code>Reader</code> as a list of Strings, one entry per line.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from, not null
	 * @return the list of Strings, never null
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static List<String> readLines(Reader input) throws IOException {
		BufferedReader reader = new BufferedReader(input);
		List<String> list = new ArrayList<String>();
		String line = reader.readLine();
		while (line != null) {
			list.add(line);
			line = reader.readLine();
		}
		return list;
	}

	// -----------------------------------------------------------------------
	/**
	 * Convert the specified string to an input stream, encoded as bytes using the default character
	 * encoding of the platform.
	 * 
	 * @param input
	 *          the string to convert
	 * @return an input stream
	 * @since Commons IO 1.1
	 */
	public static InputStream toInputStream(String input) {
		byte[] bytes = input.getBytes();
		return new ByteArrayInputStream(bytes);
	}

	/**
	 * Convert the specified string to an input stream, encoded as bytes using the specified character
	 * encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * 
	 * @param input
	 *          the string to convert
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws IOException
	 *           if the encoding is invalid
	 * @return an input stream
	 * @since Commons IO 1.1
	 */
	public static InputStream toInputStream(String input, String encoding) throws IOException {
		byte[] bytes = encoding != null ? input.getBytes(encoding) : input.getBytes();
		return new ByteArrayInputStream(bytes);
	}

	// write byte[]
	// -----------------------------------------------------------------------
	/**
	 * Writes bytes from a <code>byte[]</code> to an <code>OutputStream</code>.
	 * 
	 * @param data
	 *          the byte array to write, do not modify during output, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(byte[] data, OutputStream output) throws IOException {
		if (data != null) {
			output.write(data);
		}
	}

	/**
	 * Writes bytes from a <code>byte[]</code> to chars on a <code>Writer</code> using the default
	 * character encoding of the platform.
	 * <p>
	 * This method uses {@link String#String(byte[])}.
	 * 
	 * @param data
	 *          the byte array to write, do not modify during output, null ignored
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(byte[] data, Writer output) throws IOException {
		if (data != null) {
			output.write(new String(data));
		}
	}

	/**
	 * Writes bytes from a <code>byte[]</code> to chars on a <code>Writer</code> using the specified
	 * character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method uses {@link String#String(byte[], String)}.
	 * 
	 * @param data
	 *          the byte array to write, do not modify during output, null ignored
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(byte[] data, Writer output, String encoding) throws IOException {
		if (data != null) {
			if (encoding == null) {
				write(data, output);
			}
			else {
				output.write(new String(data, encoding));
			}
		}
	}

	// write char[]
	// -----------------------------------------------------------------------
	/**
	 * Writes chars from a <code>char[]</code> to a <code>Writer</code> using the default character
	 * encoding of the platform.
	 * 
	 * @param data
	 *          the char array to write, do not modify during output, null ignored
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(char[] data, Writer output) throws IOException {
		if (data != null) {
			output.write(data);
		}
	}

	/**
	 * Writes chars from a <code>char[]</code> to bytes on an <code>OutputStream</code>.
	 * <p>
	 * This method uses {@link String#String(char[])} and {@link String#getBytes()}.
	 * 
	 * @param data
	 *          the char array to write, do not modify during output, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(char[] data, OutputStream output) throws IOException {
		if (data != null) {
			output.write(new String(data).getBytes());
		}
	}

	/**
	 * Writes chars from a <code>char[]</code> to bytes on an <code>OutputStream</code> using the
	 * specified character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method uses {@link String#String(char[])} and {@link String#getBytes(String)}.
	 * 
	 * @param data
	 *          the char array to write, do not modify during output, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(char[] data, OutputStream output, String encoding) throws IOException {
		if (data != null) {
			if (encoding == null) {
				write(data, output);
			}
			else {
				output.write(new String(data).getBytes(encoding));
			}
		}
	}

	// write String
	// -----------------------------------------------------------------------
	/**
	 * Writes chars from a <code>String</code> to a <code>Writer</code>.
	 * 
	 * @param data
	 *          the <code>String</code> to write, null ignored
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(String data, Writer output) throws IOException {
		if (data != null) {
			output.write(data);
		}
	}

	/**
	 * Writes chars from a <code>String</code> to bytes on an <code>OutputStream</code> using the
	 * default character encoding of the platform.
	 * <p>
	 * This method uses {@link String#getBytes()}.
	 * 
	 * @param data
	 *          the <code>String</code> to write, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(String data, OutputStream output) throws IOException {
		if (data != null) {
			output.write(data.getBytes());
		}
	}

	/**
	 * Writes chars from a <code>String</code> to bytes on an <code>OutputStream</code> using the
	 * specified character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method uses {@link String#getBytes(String)}.
	 * 
	 * @param data
	 *          the <code>String</code> to write, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(String data, OutputStream output, String encoding) throws IOException {
		if (data != null) {
			if (encoding == null) {
				write(data, output);
			}
			else {
				output.write(data.getBytes(encoding));
			}
		}
	}

	// write StringBuffer
	// -----------------------------------------------------------------------
	/**
	 * Writes chars from a <code>StringBuffer</code> to a <code>Writer</code>.
	 * 
	 * @param data
	 *          the <code>StringBuffer</code> to write, null ignored
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(StringBuffer data, Writer output) throws IOException {
		if (data != null) {
			output.write(data.toString());
		}
	}

	/**
	 * Writes chars from a <code>StringBuffer</code> to bytes on an <code>OutputStream</code> using
	 * the default character encoding of the platform.
	 * <p>
	 * This method uses {@link String#getBytes()}.
	 * 
	 * @param data
	 *          the <code>StringBuffer</code> to write, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(StringBuffer data, OutputStream output) throws IOException {
		if (data != null) {
			output.write(data.toString().getBytes());
		}
	}

	/**
	 * Writes chars from a <code>StringBuffer</code> to bytes on an <code>OutputStream</code> using
	 * the specified character encoding.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method uses {@link String#getBytes(String)}.
	 * 
	 * @param data
	 *          the <code>StringBuffer</code> to write, null ignored
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void write(StringBuffer data, OutputStream output, String encoding) throws IOException {
		if (data != null) {
			if (encoding == null) {
				write(data, output);
			}
			else {
				output.write(data.toString().getBytes(encoding));
			}
		}
	}

	// writeLines
	// -----------------------------------------------------------------------
	/**
	 * Writes the <code>toString()</code> value of each item in a collection to an
	 * <code>OutputStream</code> line by line, using the default character encoding of the platform
	 * and the specified line ending.
	 * 
	 * @param lines
	 *          the lines to write, null entries produce blank lines
	 * @param lineEnding
	 *          the line separator to use, null is system default
	 * @param output
	 *          the <code>OutputStream</code> to write to, not null, not closed
	 * @throws NullPointerException
	 *           if the output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void writeLines(Collection<?> lines, String lineEnding, OutputStream output) throws IOException {
		if (lines == null) { return; }
		if (lineEnding == null) {
			lineEnding = LINE_SEPARATOR;
		}
		for (Iterator<?> it = lines.iterator(); it.hasNext();) {
			Object line = it.next();
			if (line != null) {
				output.write(line.toString().getBytes());
			}
			output.write(lineEnding.getBytes());
		}
	}

	/**
	 * Writes the <code>toString()</code> value of each item in a collection to an
	 * <code>OutputStream</code> line by line, using the specified character encoding and the
	 * specified line ending.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * 
	 * @param lines
	 *          the lines to write, null entries produce blank lines
	 * @param lineEnding
	 *          the line separator to use, null is system default
	 * @param output
	 *          the <code>OutputStream</code> to write to, not null, not closed
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if the output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void writeLines(Collection<?> lines, String lineEnding, OutputStream output, String encoding)
			throws IOException {
		if (encoding == null) {
			writeLines(lines, lineEnding, output);
		}
		else {
			if (lines == null) { return; }
			if (lineEnding == null) {
				lineEnding = LINE_SEPARATOR;
			}
			for (Iterator<?> it = lines.iterator(); it.hasNext();) {
				Object line = it.next();
				if (line != null) {
					output.write(line.toString().getBytes(encoding));
				}
				output.write(lineEnding.getBytes(encoding));
			}
		}
	}

	/**
	 * Writes the <code>toString()</code> value of each item in a collection to a <code>Writer</code>
	 * line by line, using the specified line ending.
	 * 
	 * @param lines
	 *          the lines to write, null entries produce blank lines
	 * @param lineEnding
	 *          the line separator to use, null is system default
	 * @param writer
	 *          the <code>Writer</code> to write to, not null, not closed
	 * @throws NullPointerException
	 *           if the input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void writeLines(Collection<?> lines, String lineEnding, Writer writer) throws IOException {
		if (lines == null) { return; }
		if (lineEnding == null) {
			lineEnding = LINE_SEPARATOR;
		}
		for (Iterator<?> it = lines.iterator(); it.hasNext();) {
			Object line = it.next();
			if (line != null) {
				writer.write(line.toString());
			}
			writer.write(lineEnding);
		}
	}

	// copy from InputStream
	// -----------------------------------------------------------------------
	/**
	 * Copy bytes from an <code>InputStream</code> to an <code>OutputStream</code>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * <p>
	 * Large streams (over 2GB) will return a bytes copied value of <code>-1</code> after the copy has
	 * completed since the correct number of bytes cannot be returned as an int. For large streams use
	 * the <code>copyLarge(InputStream, OutputStream)</code> method.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @return the number of bytes copied
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @throws ArithmeticException
	 *           if the byte count is too large
	 * @since Commons IO 1.1
	 */
	public static int copy(InputStream input, OutputStream output) throws IOException {
		long count = copyLarge(input, output);
		if (count > Integer.MAX_VALUE) { return -1; }
		return (int) count;
	}

	/**
	 * Copy bytes from a large (over 2GB) <code>InputStream</code> to an <code>OutputStream</code>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @return the number of bytes copied
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.3
	 */
	public static long copyLarge(InputStream input, OutputStream output) throws IOException {
		byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
		long count = 0;
		int n = 0;
		while (-1 != (n = input.read(buffer))) {
			output.write(buffer, 0, n);
			count += n;
		}
		return count;
	}

	/**
	 * Copy bytes from an <code>InputStream</code> to chars on a <code>Writer</code> using the default
	 * character encoding of the platform.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * <p>
	 * This method uses {@link InputStreamReader}.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void copy(InputStream input, Writer output) throws IOException {
		InputStreamReader in = new InputStreamReader(input);
		copy(in, output);
	}

	/**
	 * Copy bytes from an <code>InputStream</code> to chars on a <code>Writer</code> using the
	 * specified character encoding.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedInputStream</code>.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * This method uses {@link InputStreamReader}.
	 * 
	 * @param input
	 *          the <code>InputStream</code> to read from
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void copy(InputStream input, Writer output, String encoding) throws IOException {
		if (encoding == null) {
			copy(input, output);
		}
		else {
			InputStreamReader in = new InputStreamReader(input, encoding);
			copy(in, output);
		}
	}

	// copy from Reader
	// -----------------------------------------------------------------------
	/**
	 * Copy chars from a <code>Reader</code> to a <code>Writer</code>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * <p>
	 * Large streams (over 2GB) will return a chars copied value of <code>-1</code> after the copy has
	 * completed since the correct number of chars cannot be returned as an int. For large streams use
	 * the <code>copyLarge(Reader, Writer)</code> method.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @return the number of characters copied
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @throws ArithmeticException
	 *           if the character count is too large
	 * @since Commons IO 1.1
	 */
	public static int copy(Reader input, Writer output) throws IOException {
		long count = copyLarge(input, output);
		if (count > Integer.MAX_VALUE) { return -1; }
		return (int) count;
	}

	/**
	 * Copy chars from a large (over 2GB) <code>Reader</code> to a <code>Writer</code>.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @param output
	 *          the <code>Writer</code> to write to
	 * @return the number of characters copied
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.3
	 */
	public static long copyLarge(Reader input, Writer output) throws IOException {
		char[] buffer = new char[DEFAULT_BUFFER_SIZE];
		long count = 0;
		int n = 0;
		while (-1 != (n = input.read(buffer))) {
			output.write(buffer, 0, n);
			count += n;
		}
		return count;
	}

	/**
	 * Copy chars from a <code>Reader</code> to bytes on an <code>OutputStream</code> using the
	 * default character encoding of the platform, and calling flush.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * <p>
	 * Due to the implementation of OutputStreamWriter, this method performs a flush.
	 * <p>
	 * This method uses {@link OutputStreamWriter}.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void copy(Reader input, OutputStream output) throws IOException {
		OutputStreamWriter out = new OutputStreamWriter(output);
		copy(input, out);
		// XXX Unless anyone is planning on rewriting OutputStreamWriter, we
		// have to flush here.
		out.flush();
	}

	/**
	 * Copy chars from a <code>Reader</code> to bytes on an <code>OutputStream</code> using the
	 * specified character encoding, and calling flush.
	 * <p>
	 * This method buffers the input internally, so there is no need to use a
	 * <code>BufferedReader</code>.
	 * <p>
	 * Character encoding names can be found at <a
	 * href="http://www.iana.org/assignments/character-sets">IANA</a>.
	 * <p>
	 * Due to the implementation of OutputStreamWriter, this method performs a flush.
	 * <p>
	 * This method uses {@link OutputStreamWriter}.
	 * 
	 * @param input
	 *          the <code>Reader</code> to read from
	 * @param output
	 *          the <code>OutputStream</code> to write to
	 * @param encoding
	 *          the encoding to use, null means platform default
	 * @throws NullPointerException
	 *           if the input or output is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static void copy(Reader input, OutputStream output, String encoding) throws IOException {
		if (encoding == null) {
			copy(input, output);
		}
		else {
			OutputStreamWriter out = new OutputStreamWriter(output, encoding);
			copy(input, out);
			// XXX Unless anyone is planning on rewriting OutputStreamWriter,
			// we have to flush here.
			out.flush();
		}
	}

	// content equals
	// -----------------------------------------------------------------------
	/**
	 * Compare the contents of two Streams to determine if they are equal or not.
	 * <p>
	 * This method buffers the input internally using <code>BufferedInputStream</code> if they are not
	 * already buffered.
	 * 
	 * @param input1
	 *          the first stream
	 * @param input2
	 *          the second stream
	 * @return true if the content of the streams are equal or they both don't exist, false otherwise
	 * @throws NullPointerException
	 *           if either input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 */
	public static boolean contentEquals(InputStream input1, InputStream input2) throws IOException {
		if (!(input1 instanceof BufferedInputStream)) {
			input1 = new BufferedInputStream(input1);
		}
		if (!(input2 instanceof BufferedInputStream)) {
			input2 = new BufferedInputStream(input2);
		}

		int ch = input1.read();
		while (-1 != ch) {
			int ch2 = input2.read();
			if (ch != ch2) { return false; }
			ch = input1.read();
		}

		int ch2 = input2.read();
		return (ch2 == -1);
	}

	/**
	 * Compare the contents of two Readers to determine if they are equal or not.
	 * <p>
	 * This method buffers the input internally using <code>BufferedReader</code> if they are not
	 * already buffered.
	 * 
	 * @param input1
	 *          the first reader
	 * @param input2
	 *          the second reader
	 * @return true if the content of the readers are equal or they both don't exist, false otherwise
	 * @throws NullPointerException
	 *           if either input is null
	 * @throws IOException
	 *           if an I/O error occurs
	 * @since Commons IO 1.1
	 */
	public static boolean contentEquals(Reader input1, Reader input2) throws IOException {
		if (!(input1 instanceof BufferedReader)) {
			input1 = new BufferedReader(input1);
		}
		if (!(input2 instanceof BufferedReader)) {
			input2 = new BufferedReader(input2);
		}

		int ch = input1.read();
		while (-1 != ch) {
			int ch2 = input2.read();
			if (ch != ch2) { return false; }
			ch = input1.read();
		}

		int ch2 = input2.read();
		return (ch2 == -1);
	}

}
